<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="../../jquery.min.js"></script>
</head>
<body>
    <div class="sky">
        1
    </div>
    <div class="sky">2</div>
</body>
<script>
    $('.sky').hide();//hide和show方法是可以针对多个dom的
</script>
</html>